Goby Help

[Camer0n]

I have a new 120 gallon tank and one of my first fish is a pink spot Goby. He as been acting kind of weird. He swims around at the top of the tank a lot and along the glass, but today he started perching on the side of the overflow and lightly breaking the surface a lot. Is this normal behavior?? Do I need more oxygen in my water???

 

[johnike]

Are the rest of the fish alright?
How old is the tank, and have you tested Ammonia?
How many more fish in the tank?